Production of dialkyl ethers



Patented Apr. 2, 1946 I umrso STATES- PATENT OFFICE '13:: Zifififfili.

American Cyanamid Company, N. Y., a corporation of Maine No Drawing.

New York, i

Serial No. 404,203. Divided and this application December 30, 1941, Serial No. 424,949

4 Claims.

This invention relates to the production dialkyl ethers of dimethylol urea and is more particularly concerned with the production of the dimethyl and (ll-ethyl ethers.

Many and varying processes have been suggested and used for the production of the ethers of dimethylol urea by the reaction of the latter material with various alcohols. When the higher alcohols are used in this reaction, the process is relatively simple and yields are sufiiciently good for commercial purposes. However, in the production of the methyl and ethyl ethers, on a commercial scale, the yields obtained are much lower and, as a result, the large scale production of these ethers hasnot been found to be practicable.

As described in my application Serial No.

404,203 filed July 26, 1941, of which this is a division,'I have found that these alkyl ethers of dimethylol urea may be prepared commercially by a simple and economical process with a practically 100% yield of theoretical. Stated generally, the process involves the reaction of the alcohols with dimethylol urea under acid conditions at a pH below 4 and at a temperature below 30 C.,,the. acidity of the reaction mixture being regulated by the use of such acids as can be removed from the solution by precipitation with a base capable of forming a salt with the acid substantially insoluble in the reaction mix- 90 C. is reached. ,At this time thelast traces of water are removed by adding toluol in an amount equal to about 20% of the calculated yield, and distillation is continued in vacuo at about 80 C. until the toluol and water are removed. The resultant product is a clear melt which may then be dumped in trays or the like ture, thus giving a solution free from electrolytes.

' added sufflcient barium hydroxide to precipitate barium oxalate and thereby remove the oxalic acid from the solution. A slight excess of barium hydroxide is used to give a pH of 7.5-8.0. The precipitated barium oxalate is removed by filtration and the filtrate is concentrated in vacuo (26-28 inches) by heating to a temperature not exceeding 50 C. until the greater part of the excess methyl alcohol and water has been removed. At this point, the solution contains about 60% solids.

The ether solution is further concentrated in vacuo as above, the heating and concentration belngcontinued until a tempera.

of about and allowed to harden to a mass which is resinous in general appearance but which consists of crystals bonded together with a resinous material. The nitrogen content of this resinous or semi-crystalline product indicates a degree of purity equivalent to 104% since the product contains about of the dimethyl ether of dimethylol urea and about 10% partially demethylated ether.

In place of the methyl alcohol in the above example I may utilize ethyl alcohol to prepare the corresponding di-ethyl ethers of dimethylol urea. Likewise other alcohols may be substituted, e. g., propyl, butyl, etc. In place of oxalic acid and barium hydroxide there may be used such other combinations of acids and bases as will produce a salt substantially insoluble in the ethers may also be mixed with various cellulose esters and ethers in suitable solvents.

Suitable other changes and variations may be made in carrying out the invention without departing from the spirit and scope thereof as defined in the appended claims.

.I claim: a

1. The process which comprises preparing a mixture of dimethylol urea with an aliphatic alcohol selected from the group consisting c-f methyl andv ethyl alcohols and an acid capable of forming an insoluble metal salt, the amount of acid being such as to make the mix more acid than pH 4, reacting the mixture at temperatures below 30 C. until-a clear solution is obtained,

adding a soluble metal compound of the nature and in an amount sufllcient to remove the acid as arr-insoluble metal salt, removing the precipitated metal salt, concentrating the remaining solution in vacuo until a temperature of about 90 C. is reached and removing the rest of the water by adding toluol and distilling at about 80 C.

2. The process which comprises preparing a mixture of dimethylol urea with an aliphatic alcohol selected from the group consisting of methyl and ethyl alcohols and oxalic acid in an amount sufficient to make the mixture more acid than pH 4, reacting the mixture below 30 C.

-until a clear solution is obtained, adding suflicient barium hydroxide to the solution to give a pH of about 7.5; removing precipitated barium oxalate, concentrating the remaining solution in vacuo until a temperature of about 90 C. is reached and removing the rest of the water by adding toluol and distilling at about 80- 0.

tained, adding suficient barium hydroxide to the solution to give a pH of about 7.5;removing recipitated barium oxalate, concentrating the remaining solution in vacuo until a temperature of about 90 C. is reached and removing the'rest of the water by adding toluol and distilling at about 80 C.

4. A process which comprises preparing a mixture f dimethylol-urea with methyl alcohol, and an acid capable oi forming an insoluble metal salt, the amount'cf acid being such as to make 3. The process which comprises preparing a mixture of dimethylol urea with methyl alcohol and oxalic acid in an amount suflicient to make the mixture more acid than pH 4, reacting the mixture below 30 C. until a clear solution is ob- 

